A drainage apparatus is used for draining fluid from a human body cavity or wound to promote healing, such as after chest surgery. The apparatus usually comprises a suction pump, a collection container which is often connected with an underwater seal container, and a drainage tube having a distal and a proximal end. The proximal end of this tube is connected to a catheter which is introduced in the body cavity, the distal end extends into the collection container or the underwater seal container respectively. The negative pressure applied has to be chosen carefully, since excessive pressure may damage delicate tissues in the body cavity.
Blood or tissue clots however can clog the catheter or the drainage tube, such that the fluids can no longer readily drain into the fluid collection container but tend to built up in the catheter, the drain tube or may even remain in the cavity. It is therefore necessary to sometimes vent the body cavity to remove drainage fluids.
It is known to use an auxiliary line whose proximal end is in fluid contact with the drainage line. This auxiliary line is used to supply air or a gas to the drainage line. The supply is controlled by a valve and a pressure sensor. Such an apparatus is for example described in U.S. Pat. No. 5,738,656.
However, the catheter and the drainage tube have still to be removed and cleaned, when they are clogged.